Electrical snap switch arrangement



March 24, 1964 w. scHNl-:cK ETAL 3,126,461 ELECTRICAL SNAP SWITCH ARRANGEMENT Filed June 1, 1959 F/G. f

United States Patent Oiice 3,126,461 Patented Mar. 24, 1964 3,126,461 ELEC'ERCAL SNAP SWITCH ARRANGEMENT Werner Schnack, Stuttgart, and @tto Herrmann, Stuttgart- Botnang, (Germany, assignors to Robert Bosch G.m.h.H., Stuttgart, Germany Filed .inne 1, 1959, Ser. No. 817,368 Claims priority, application Germany, Enne 4, 1958 8 Claims. (Cl. 20h-67) The present invention relates to electrical switches.

More particularly, the present invention relates to irnprovements in the switch structure shown in U.S. Patent 2,810,035 which shows a switch arrangement suitable for use with refrigerators and the like.

It is an object of the present invention to provide an exceedingly simple switch arrangement.

It is another object of the present invention to provide a switch arrangement whose parts are of rugged construction and will operate very reliably over a long period of time to produce the desired result.

With the above objects in view the present invention includes in a switch arrangement an elongated springy contact-carrying switch blade having two faces and movable between a switchopen position and a switch-closing position and, in accordance with the present invention, a lever means which acts in only one direction on one face of the switch blade to move the latter from one to the other of these positions thereof, the swtch blade itself having the capability due to its own inherent resiliency to return from the other back to the one position thereof.

T ie novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of certain speciiic embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a sectional elevational View of a switch arrangement including the structure of the invention, the section of FIG. 1 being taken along the line I-I of FIG. 2 as seen in the direction of arrows;

FIG. 2 is a section taken along the line II-II of FIG. l, as seen in the direction of arrows;

FIG. 3 is an enlarged fragmentary detail view of a modification;

FIG. 4 is a plan View of a switch blade which may be utilized in the switch arrangement of FIGS. 1 to 3; and

FIG. 5 is a side elevational view of the switch blade, the switch-closing position of the blade being shown in phantom lines.

The structure of the present invention is an improvement and simplification of the structure shown in U.S. Patent 2,810,035.

The switch arrangement comprises a bell crank 74 which, in contrast to the bell crank structure of US. Patent 2,810,035, is in the form of a one-piece casting. This bell crank '74 is pivotally carried by a suitable pivot pin 12 which is carried by the support structure or housing 50 of the switch, in the same way in which the bell crank of the U.S. Patent 2,810,035 is supported for turning movement. The bell crank 74 has an upwardly directed arm 74a, as Viewed in FIG. 1, and this arm 74a carries a means for transmitting movement of the bell crank to a switch blade 75. This means for transmitting the movement of the bell crank to the switch blade 75 includes an elongated pin 33 which is screwed into a threaded bore of the upwardly directed arm 74a of the bell crank 74, as viewed in FIG. 1, so that the axial position of the pin 33 can be adjusted.

It will be noted that the switch blade 75, which is shown in its switch-open position in FIG. 2, is acted upon on only one of its faces by the lever means 33, 74. This switch blade which is in the form of an elongated springy strip (see FIG. 4) carrying a Contact 40, is so constructed that when the bell crank 74 turns in a clockwise direction, as viewed in FIG. l, back to a position illustrated in FIG. 1, the switch blade 75 will as a result of its own inherent resiliency follow the pin 33 and will automatically return to the switch-open position illustrated in FIG. 2. Of course, when the switch blade 75 is in its switch-closing position (see the phantom-line position of this blade in FIG. 5) the contact 40 engages a contact 42 shown in FIG. 2.

As is apparent from FIG. 2, the switch structure includes a support means made up in part of a body 77 of electrically non-conductive material, and this body 77 is provided with a projection 77a to which an end 76 of the switch blade 75 is iixed by a screw 78, so that the switch blade 75 is supported at only one end portion thereof on the support means of the switch arrangement. The opposite end portion 79 of the switch blade can swing freely and carries the contact 40 as pointed out above. In the illustrated switch-open position of the switch, as is apparent from FIG. 2, the Contact 40 engages a stop 80 in the form of a pin which embodies suitable adjusting means adapted to change its distance from the contact 42. In the illustrated example this adjusting means takes the form of threads on the exterior surface of the pin titl cooperating with threads in the bore of the body 77 through which the pin 80 extends, so that this threaded structure serves as a means for axially adjusting the stop titl to thereby control the latters position with respect to the stationary contact d2.

At the side of switch blade 75 opposed to the pin 33 there is located a leaf spring means which includes an elongated leaf spring 81 fixed to an electrically non-conductive pin 82 made of plastic, for example, and this pin S?. is supported in an opening 77]) of the body 77, so that in this way the leaf spring 81 is supported at the elevation of the switch blade 75. At its end which is nearest to the screw 7S the leaf spring 81 is provided with an end portion S3 formed with a notch through which the switch blade 75 extends so that in this way the end portion 83 embraces the switch blade to enable the latter to prevent turning of the leaf spring Si. The pin 82 is slidable in the opening 77b of the support 77 and is provided with a head end directed toward the switch blade '75 and pressing against the latter when the switch blade is in its switch-closing position in which the contact 443 engages the contact 42.

The one-piece casting which forms the bell crank 74 is provided at the lower arm of the bell crank, as viewed in FIG. 1, with a projection 84 to which one end of a spring means 2&5 is connected, this spring means serving as a return spring for returning the parts to the position shown in the drawings. The other end of the spring means 2li is connected by a suitable connecting means to a lever 25 which cooperates with a cam 30 in a manner similar to the manner in which the elements 2.5 and 30 cooperate in the switch of U.S. Patent 2,810,035. In the embodiment of FIG. 1, the upper end of the coil spring 24 has its convolutions embedded in a block 8S of plastic material, this block S5 being provided with a threaded bore $6 into which a screw 87 threadedly extends, so that the screw 87 supports the block 35. The screw S7 is provided with a head 88 whose bottom surface forms part of a sphere engaging the upper concave surface 89 of a recess in the lever 25, this lever 25 being a onearmed lever. Because of the curvature of the recess Sg and head 33 these elements cooperate in the manner of a ball and socket joint, and the bore in the lever 25 through which the shank of the screw 8'7 passes is provided with suflicient clearance to permit the turning of the screw 87 with respect to the lever 25 which will enable the screw 87 to adapt itself to any inclination of the one-armed lever 25 brought about by the manual turning of the cam 3). This lever 25 engages the periphery of the cam 3) and is connected at an end portion distant from the cam 3G to the wall 52 of the switch housing 53. In accordance with the present invention the cam 3i) as well as the cam shaft 36a which carries the same form a one-piece casting. The cam 30 is rotatable in a supporting member 47 which is mounted within and is secured to the switch housing t?. The cam shaft 30a carries a knob 32 which may adjust the cam 36 to provide the desired initial stress in the spring 24.

As is the case in U.S. Patent 2,810,035, a uid introduced into the hollow expandible container i9, through a conduit 22 is capable of expanding the left wall of the container 19, as viewed in FIG. l, toward the bell crank 74 so as to shift a member 18 fixed to the movable left wall of the container 19, as viewed in FIG. l, to the left and thus turn the bell crank 74 in a counterclockwise direction, as viewed in FIG. l. Thus, the parts 1S and 19 form a lever-moving means. Upon turning of the bell crank 74 in a counterclockwise direction as a result of expansion of the container 19, the motion transmitting pin 33 will act only on the right face of the switch blade '75, as viewed in FIGS. 1 and 2, deforming the springy switch blade until nally it moves over into its other position in which the contact 4t) engages the contact 42 in order to close the switch. When the bell crank 74 returns to its rest position under the action of the return spring 24, the switch blade 75 automatically moves back to its switch-open position in which the contact 40 engages the stop Si) due to the resiliency of the switch blade 75 itself. During this return movement of the switch blade 75 to the position thereof illustrated in FIG. 2, which is to say at least during the initial part of this return movement, the leaf spring 81 presses the head end of the pin 82 against the switch blade 75 to assist the latter in its return movement to the position illustrated in FIG. 2, the pin 82 being slidable in the opening 77b of the support 77, as pointed out above. The adjustment of the stop 80 controls the range within which the switch is capable of controlling temperature, for example. Thus, where the switch structure of the invention is used in a refrigerator, the adjustment of the screw 30 will control the range between the upper temperature at which the switch will automatically close and the lower temperature at which the switch will automatically open.

The screw member 71 shown at the lower part of FIG. 1 limits the turning of the bell crank 74 by engaging the projection 84 of the latter when this bell crank 74 turns in a counterclockwise direction, as viewed in FIG. l, to move the switch blade 75 to the switchclosing position. The angular position of the cam 30 will adjust the tension of the spring means 24 for the purpose of adjusting the temperature of the refrigerator at which the switch will open, within predetermined limits.

The switch arrangement of the invention is simple in its construction so that the switch housing 5t) can also be simpliiied. As a result of the ease and convenience with which adjustments can be made with the simple structure of the invention an improved control is provided.

Instead of the illustrated connecting means 85, S7 for connecting the spring 24 to the lever 25, the spring can have its upper convolutions threaded onto the exterior threads of a block member 85', shown in FIG. 3, which is in turn threadedly connected with the screw S7. Furthermore, if desired, the screw 87 itself may be provided along its lower half, as viewed in FIG. 1, with a portion of enlarged diameter provided with exterior threads onto which the upper convolutions of the spring 24 are threaded, so that in this way a single one-piece screw member 87, 35 carried by the lever 25 can cooperate directly with the spring 24 to be turned with respect to the latter for adjusting the tension thereof.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of switches differing from the types described above.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specic aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a switch arrangement, in combination, support means; an elongated springy contact-carrying switch blade carried by said support means and assuming due to its own resiliency a first position; lever-moving means carried by said support means and spaced from said switch blade; a bell crank lever turnably carried by said support means and having one arm located between said switch blade and said lever moving means so that when the latter operates it moves said arm of said bell crank toward said switch blade; and means carried by said arm of said bell crank and engaging said switch blade at the side thereof which is directed toward said lever moving means for transmitting movement of said lever to said switch blade for placing the latter in a `second position when said lever moving means operates, one of said positions of said switch blade being a switch-open position and the other of said positions of said switch blade being a switch-closed position.

2. In an arrangement as recited in claim 1, said bell crank being in the form of a one-piece casting formed in said arm thereof with a threaded opening and said means for transmitting movement of said arm to said switch blade being in the form of an elongated pin thread ed in said opening of said arm of said bell crank so that the position of said pin with respect to said bell crank may be adjusted.

3. In a switch arrangement, in combination, an elongated spring contact-carrying switch blade having a switchopen position and a switch-closed position; lever means acting on one face of said blade for moving the latter from one to the other of said positions thereof; and leaf spring means pressing against the opposite face of said switch blade at least when the latter is in said other position thereof, said leaf spring means including an elongated leaf spring and an electrically non-conductive pin carried by said leaf spring and having a head directly engaging said switch blade at said opposite face thereof when said blade is in said other position thereof.

4. In a switch arrangement, in combination, a support means; an elongated springy switch blade iixed at only one end portion thereof to said support means; a first contact carried by said switch blade `adjacent an opposite end thereof; a second contact carried by said support means to be engaged by said first contact when said switch blade is in a switch-closed position, said switch blade assuming due to its own resiliency a switch-open position where said rst contact is spaced from said second contact; a stop carried by said support means and engaging said rst contact when said blade is in said switch-open position thereof; means for adjusting the distance of said stop from said second contact so as to regulate the extent to which said switch blade must be moved to move said rst contact into engagement with said second contact; and means acting in only one direction on said switch blade for actuating the latter to move said rst Contact away from said stop into engagement with said second contact.

5. In a switch arnangement, in combination, support means; an elongated springy contact-carrying switch blade carried by said support means and having two faces and movable between a switch-open position and a switchclosed position; a bell cnank turnably carried by said support means and having only one arm located at the elevation of said switch blade; motion transmitting means carried by said one arm for transmitting turning of said bell crank to said switch blade for moving the latter from one to the other of said positions thereof when said bell crank turns in one direction during movement of said one arm of said bell crank toward one face of said switch blade; spring means operatively connnected with the other arm of said bell crank for rurging lthe latter to turn in an opposite direction; a manually turnable cam carried by said support means; `a second lever carried by said support means `and engaging said cam; and means connecting said spring means to said second lever so that the angular position of said cam adjusts the tension of said spring means, said means connecting said spring means to said second lever including threaded portions capable of being tur-ned one with respect to the other for adjusting the tensioning of said spring means with respect to said second lever, and said threaded portions including at least one screw member having -a head forming part of a sphere, said second lever having a recess also forming part of a sphere and engaged by said head of said screw member.

6. In a switch arrangement, in combination, support means; an elongated spring contact-carrying switch blade carried by said support means and having two faces and movable between a switch-open position and a switchclosed position; a bell crank turnably carried by said support means and having only one arm located at the elevation of said switch blade; motion transmitting means carried by said one arm for transmitting turning of said bell crank to said switch blade for moving the latter from one to the other of said positions thereof when said bell crank turns in one direction during movement of said one arm of said bell crank toward one face of said switch blade; spring means operatively connected with the other arm of said bell crank for urging the latter to turn in an opposite directions; a manually turnable cam carried by said support means; a second lever carried by said support means and engaging said cam; and means connecting said spring means to said second lever so that the angular position of said cam adjusts the tension of said spring means, said means connecting said spring means to said second lever including threaded portions capable of being turned one with respect to the other for adjusting the tensioning of said spring means with respect to said second lever, and said threaded portions including at least one screw member having a head forming part of a sphere, said second lever having a recess also forming part of a sphere and engaged by said head of said Screw member, and said means connecting said spring means to said second lever including in addition to said screw member a block threadedly carried by said screw member and formed with exterior threads, said spring means being in the form of a coil spring having at one end convolutions threaded onto the latter threads.

7. In a switch arrangement, in combination, support means; an elongated spring contact-carrying switch blade carried by said support means and having two faces and movable between a switch-open position and a switchclosed position; a bell crank turnably carried by said support means and having only one arm located at the elevation of said switch blade; motion transmitting means carried by said one arm for transmitting turning of said bell crank to said switch blade for moving the latter from one to the other of said positions thereof when said bell crank turns in one direction during movement of said one arm of said bell crank toward one face of said switch blade; spring means operatively connected with the other arm of said bell crank for urging the latter to turn in an opposite direction; a manually turnable cam carried by said support means; a second lever carried by said support means and engaging said cam; and means connecting said spring means to said second lever so that the angular position of said cam adjusts the tension of said spring means, said means connecting said spring means to said second lever including threaded portions capable of being turned one with respect to the other for adjusting the tensioning of said spring means with respect to said second lever, and said threaded portions including at least one screw member having a head forming part of a sphere, said second lever having a recess also forming part of a sphere and engaged by said head of said screw member, and said means connecting said spring means to said second lever and including in addition to said screw member a block threadedly connected therewith and fixed to an end portion of said spring means.

8. In a switch arrangement, in combination, support means; an elongated spring contact-carrying switch blade carried by said support means and having two faces and movable between a switch-open position and a switchclosed position; a bell crank turnably carried by said support means and having only one arm located at the elevation of said switch blade; motion transmitting means carried by said one arm for transmitting turning of said bell crank to said switch blade for moving the latter from one to the other of said positions thereof when said bell crank turns in one direction during movement of said one arm of said bell crank toward one face of said switch blade; spring means operatively connected with the other arm of said bell crank for urging the latter to turn in an opposite direction; a manually turnable cam carried by said support means; a second lever carried by said support means and engaging said cam; and means connecting said spring means to said second lever so that the angular position of said cam adjusts the tension of said spring means, said means connecting said spring means to said second lever including threaded portions capable of being turned one with respect to the other for adjusting the tensioning of said spring means with respect to said second lever, and said threaded portions including at least one screw member having a head forming part of a sphere, said second lever having a recess also forming part of a sphere and engaged by said head of said screw member, and said means connecting said spring means to said second lever and including in addition to said screw member a block threadedly connected therewith and xed to an end portion of said spring means, said spring means including a plurality of convolutions embedded in said block.

References Cited in the file of this patent UNITED STATES PATENTS 2,743,331 Lauder et al. Apr. 24, 1956 2,810,035 Hermann et al Oct. l5, 1957 2,901,568 Goti? y Aug. 25, 1959 

3. IN A SWITCH ARRANGEMENT, IN COMBINATION, AN ELONGATED SPRING CONTACT-CARRYING SWITCH BLADE HAVING A SWITCHOPEN POSITION AND A SWITCH-CLOSED POSITION; LEVER MEANS ACTING ON ONE FACE OF SAID BLADE FOR MOVING THE LATTER FROM ONE TO THE OTHER OF SAID POSITIONS THEREOF; AND LEAF SPRING MEANS PRESSING AGAINST THE OPPOSITE FACE OF SAID SWITCH BLADE AT LEAST WHEN THE LATTER IS IN SAID OTHER POSITION THEREOF, SAID LEAF SPRING MEANS INCLUDING AN ELONGATED LEAF SPRING AND AN ELECTRICALLY NON-CONDUCTIVE PIN CARRIED BY SAID LEAF SPRING AND HAVING A HEAD DIRECTLY ENGAGING SAID SWITCH BLADE AT SAID OPPOSITE FACE THEREOF WHEN SAID BLADE IS IN SAID OTHER POSITION THEREOF. 